JP5634874B2 - Grease formulation - Google Patents

Description

  The present invention relates to grease formulations and their preparation, and the use of certain types of base oils in grease formulations.

  It is known to prepare industrial and automotive grease formulations by mixing thickeners such as soaps in suitable base oils. The oils used for this purpose typically tend to be the same type of mineral-derived base oils normally used in oil-based lubricants.

  Depending on its intended use, the properties of the grease formulation need to be carefully tailored to meet the standards and / or consumer requirements. For example, it needs to have a suitable consistency. Ideally it should show good mechanical stability and oil separation. Good oxidative stability and low temperature flow characteristics are also desirable, as are good wear resistance.

  In typical mineral oil based grease formulations, it is often difficult to achieve all of the desired properties. In such cases, one or more additives need to be included in the formulation to modify its performance. However, the inclusion of additives significantly increases the manufacturing cost of the formulation. Therefore, it would be desirable to provide a grease formulation that has certain desired properties, but with additive levels that are currently lower than required to achieve these properties.

  In addition to mineral-derived base oils, it is now also known to prepare base oils through the Fischer-Tropsch condensation process. This process is typically carried out in the presence of a suitable catalyst at elevated temperature (eg 125-300 ° C., preferably 175-250 ° C.) and / or high pressure (eg 5-100 bar, preferably 12-50 bar). A reaction that converts carbon oxides and hydrogen into longer chains, usually paraffinic hydrocarbons. A hydrogen: carbon monoxide ratio other than 2: 1 may be used if desired.

  The Fischer-Tropsch process can be used to prepare a variety of hydrocarbon fuels including LPG, naphtha, kerosene and gas oil fractions. Following hydroprocessing and vacuum distillation, heavier fractions can produce a series of base oils with different distillation characteristics and viscosities, which are useful as lubricating base oil stock solutions.

  The higher molecular weight so-called “boiler” product remaining after recovery of the lubricating base oil cut from the vacuum column is typically a lower molecular weight product that is considered unsuitable for use as the lubricating base oil itself. Usually recycled to the hydrocracking unit for conversion to product. This product is often known as an “ultra heavy” base oil cut.

  Fischer-Tropsch derived base oils tend to have excellent low temperature properties, such as a low pour point, and relatively good oxidative stability. They are also attractive because of the relatively simple process used to make them compared to similar oils prepared from mineral oil feedstocks. However, they also have a relatively low polarity as a result of the catalytic process used to prepare them. This in turn gives them a relatively low affinity (solubility) for highly polar thickeners (eg soaps) contained in the grease formulation, which is of suitable consistency or stiffness (permeability) Means that the use of relatively high thickener concentrations is required for their inclusion in grease formulations. High thickener concentrations tend to be considered undesirable due to the associated increased raw material costs. Also, it is generally believed that too high a thickener content in a grease formulation can cause problems, especially when pumping the formulation at lower temperatures. Therefore, it is considered desirable to decrease rather than increase the thickener concentration.

  It is now surprising that the use of Fischer-Tropsch derived base oils with correspondingly increasing thickener levels in grease formulations can lead to improvements in overall formulation properties and performance, especially in wear resistance. I understand. These improvements can often make up for the potential disadvantage of higher thickener content.

  Other relatively low polarity base oils are used in conventional grease formulations, but are not without their disadvantages. For example, synthetic polyalphaolefins (PAO) are sometimes used as grease bases but are suitable only for special applications due to their high cost. So-called “XHVI” (ultra-high viscosity index) oils, which are highly refined and chemically treated mineral oils, are also sometimes used in grease formulations, but these oils are only available at low viscosity, again here Their potential uses are also limited.

  Accordingly, it would be desirable to provide a grease formulation that can overcome or at least mitigate the above-mentioned problems and ideally benefit from one or more improvements in overall performance.

In accordance with a first aspect of the invention, a grease formulation is provided containing a thickener and a Fischer-Tropsch derived base oil, the Fischer-Tropsch derived base oil having a kinematic viscosity of 8-30 mm ² / s at 100 ° C. .

  The use of a Fischer-Tropsch derived base oil in a grease formulation is, as expected, more than would be required if a mineral base oil was used instead to achieve a given consistency. Requires a large amount of thickener. This is due to the relatively low polarity of Fischer-Tropsch derived oil, as described above. Nevertheless, inclusion of a Fischer-Tropsch derived base oil, and consequently higher thickener concentrations, has been found to provide significant benefits to the formulation. In particular, it improves the wear resistance properties of the formulation, and in some cases improves its copper corrosion performance, as well as increases consistency, improving oxidative stability, cold flow performance, mechanical stability, and oil separation I found out that Increasing thickener concentration and Fischer-Tropsch derived base oil appear to be able to contribute together to significantly improved properties in the overall grease formulation, the improvement being the cost associated with higher thickener concentrations. The increase can be at least partially offset.

  These improvements are in turn related to performance enhancing additives such as antiwear additives, copper corrosion inhibitors, viscosity modifiers, antioxidants, extreme pressure additives, friction modifiers, rust inhibitors, and low temperature flow additives. Allows lower levels of use, thus reducing manufacturing costs. In some cases, the grease formulation according to the present invention may not contain any such additives. Furthermore, the use of Fischer-Tropsch derived base oils themselves can play a role in reducing manufacturing costs, since such base oils tend to be produced at a lower cost than their mineral-derived counterparts.

  Fischer-Tropsch derived oils are also known to be more readily biodegradable and more pure than those derived from mineral oils. They can provide a “cleaner” replacement for mineral-derived base oils, so that they are used in environmentally sensitive fields or machinery that handles sensitive consumer products such as food, cosmetics or pharmaceuticals May be more suitable for inclusion in the intended grease formulation. This is especially likely to be true for grease formulations containing none or very low levels of additives, such as can be achieved according to the present invention.

In general, the Fischer-Tropsch derived base oil used in the grease formulation according to the invention is 5-30 or 5-25 or 5 as measured by ASTM D-445 at 100 ° C. (VK 100). It may have a kinematic viscosity of 20 mm ² / s.

Fischer-Tropsch derived base oils are preferably heavy base oils, which term includes oils known as “ultra heavy” base oils. In the case of a super heavy base oil it may have a VK 100 of for example 8 or 9 or 10 to 30 mm ² / s.

  Such high viscosity base oils with the other advantageous properties described above can be achieved using the Fischer-Tropsch process, but are generally not possible from mineral oil feedstocks. However, they are manufactured much cheaper and more readily available than synthetic high viscosity substitute polyalphaolefins.

  Fischer-Tropsch derived heavy base oils tend to exhibit better low temperature behavior than lower viscosity mineral base oils. They are also superior in comparison to their mineral-derived counterparts, and even in comparison to poly alpha-olefins, which are high viscosity synthetic polymers that are sometimes used as replacements for heavy and superheavy base oils. It also tends to have a viscosity index (which provides a measure of the temperature dependence of viscosity). They can therefore be used to increase the viscosity of grease formulations in accordance with the present invention without the need to formulate so-called “bright stock” (high viscosity mineral base oil) fractions or other viscosity modifiers.

  Currently, there are no mineral-derived base oils with viscosities comparable to Fischer-Tropsch derived superheavy base oils. Thus, the use of such a Fischer-Tropsch derived base oil in a grease formulation according to the present invention makes it possible to achieve unique grease properties, in particular the advantageous properties described above and demonstrated in the examples below. Might be.

  The Fischer-Tropsch derived base oil preferably has an initial boiling point (ASTM D-2887) of 360-460 ° C, such as 370-450 ° C or 380-445 ° C. It preferably has a final boiling point (ASTM D-2887) of 550-770 ° C., for example 560-760 ° C. or 570-750 ° C.

  It preferably has a density (IP 365/97) of 0.80 to 0.86 g / ml, for example 0.81 to 0.85 g / ml or 0.82 to 0.84 mg / ml.

  In this context, the term “Fischer-Tropsch derived” means that the material is a synthetic product of or derived from a Fischer-Tropsch condensation process, typically a Fischer-Tropsch derived wax. . The term “non-Fischer-Tropsch induction” may be interpreted accordingly. Fischer-Tropsch derived oil is therefore a hydrocarbon stream, most of which, excluding added hydrogen, is derived directly or indirectly from the Fischer-Tropsch condensation process.

  Fischer-Tropsch derived products are sometimes referred to as GTL products.

  The hydrocarbon product may be obtained directly from the Fischer-Tropsch reaction, or for example by fractional distillation of the Fischer-Tropsch synthesis product, or indirectly from the hydrotreated Fischer-Tropsch synthesis product. Hydrotreating can be accomplished by hydrocracking to adjust the boiling range (see, for example, GB-B-20207289 and EP-A-0147873) and / or by increasing the proportion of branched paraffins. It can be accompanied by hydroisomerization which can improve flow characteristics. EP-A-0583836 first applies a hydroconversion to the Fischer-Tropsch synthesis product under conditions that do not substantially undergo isomerization or hydrocracking (on olefin and oxygen-containing components). A two-stage hydrotreating process in which at least a portion of the resulting product is hydroconverted under conditions such that hydrocracking and isomerization then occurs to produce substantially paraffinic hydrocarbon fuel. It describes the law. The desired fraction may subsequently be isolated, for example by distillation.

  In order to improve the properties of the Fischer-Tropsch condensation product, polymerization, alkylation, distillation, cracking-decarboxylation, isomerism, for example as described in US Pat. No. 4,125,566 and US Pat. No. 4,478,955 Other post-synthetic treatments such as hydrogenation and hydrogenation reforming may be employed.

  Typical catalysts for the Fischer-Tropsch synthesis of paraffinic hydrocarbons contain a Group VIII metal, in particular ruthenium, iron, cobalt or nickel, as catalytically active components. Such suitable catalysts are described in EP-A-0583836 (pages 3 and 4).

  An example of the Fischer-Tropsch method is described in the paper “The Shell Middle Stildes Stilessid Stilssid Senset” in the 5th Synfuels Worldwide Symposium, Washington DC et al. Synthesis). See also the November 1989 publication of the same title from Shell International Petroleum Company Ltd, London, UK. This process (sometimes also referred to as Shell “Gas-To-Liquids” or “GTL” technology) involves the conversion of natural gas (primarily methane) derived synthesis gas to heavy long chain hydrocarbon (paraffin) waxes, A middle distillate range product can be produced and then the hydrocarbon wax can be hydroconverted and fractionated to produce a liquid transportation fuel such as gas oil that can be used in automotive diesel fuel. Base oils having various viscosities and including both light and middle distillate and heavier oils may also be produced by such methods.

  By the Fischer-Tropsch process, the Fischer-Tropsch derived oil has essentially no or undetectable levels of sulfur and nitrogen. Compounds containing these heteroatoms tend to act as catalyst poisons for Fischer-Tropsch catalysts and are therefore removed from the synthesis gas feed. In certain respects, this can provide additional advantages to the grease formulation according to the invention.

  Furthermore, the Fischer-Tropsch process produces no or substantially no aromatic components in normal operation. The aromatic content of the Fischer-Tropsch derived product is typically less than 1 wt%, preferably less than 0.5 wt%, more preferably less than 0.1 wt%, as suitably measured according to ASTM D4629.

  Generally speaking, as noted above, Fischer-Tropsch derived hydrocarbon products have relatively low levels of polar components, particularly polar surfactants, compared to, for example, mineral-derived oils. Examples of such polar constituents include oxygen-containing compounds and compounds containing sulfur and nitrogen. Since all are removed by the same process, the low level of sulfur in the Fischer-Tropsch derived oil is generally a low level indicator of both oxygenates and nitrogen containing compounds.

The Fischer-Tropsch derived base oil used in the present invention is preferably hydrocracked of a paraffinic, conveniently Fischer-Tropsch derived wax, and preferably the resulting waxy raffinate, such as a solvent or more It is preferably obtained by dewaxing by catalytic dewaxing. The paraffin wax may be a slack wax. Distilling the raffinate into a light base oil stream having a VK 100 of 2-4 mm ² / s, a heavy base oil stream having a VK 100 of about 4-8 mm ² / s, and typically about 8 mm ² / s, and Several different products can be produced, including “superheavy” base oil streams having a VK 100 of about 8-30 or 8-25 mm ² / s, typically about 20 mm ² / s. The base oil used in the present invention may be derived in particular from the latter two base oil streams.

  Fischer-Tropsch derived heavy base oil is preferably derived from a Fischer-Tropsch “bottom” (ie high boiling) product, either directly or indirectly, following one or more downstream processing steps. Base oil. Fischer-Tropsch bottoms are hydrocarbon products that are recovered from the bottom of a fractionation column, usually a vacuum column, following fractionation of a Fischer-Tropsch derived feed stream. For example, WO 02070629 describes a method for preparing an isoparaffinic base oil from a wax made by the Fischer-Tropsch process, and the product of such a process is found in the grease formulation according to the invention. May be used.

  Since the base oil used in the present invention is derived from Fischer-Tropsch products (typically waxes), it is generally essentially paraffinic and typically contains a majority amount of isoparaffins. Preferably the base oil is a paraffinic base oil having a paraffin content greater than 80% by weight. It preferably has a saturate content of greater than 98% by weight (as measured by IP-386) and an n-paraffin content of less than 0.1% by weight, and in some cases none (ie its i: n ratio is typical) Extremely high).

  Preferably it contains a hydrocarbon molecule having a continuous number of carbon atoms so as to include a series of isoparaffins having n, n + 1, n + 2, n + 3 and n + 4 (where n is 20 to 35) carbon atoms. . This series is a consequence of the Fischer-Tropsch hydrocarbon synthesis reaction from which the base oil is derived following the isomerization of the wax feed.

  Preferably the saturate content of the base oil is greater than 99 wt%, more preferably greater than 99.5 wt%.

  The base oil preferably has a naphthenic compound content of 0-20% by weight, more preferably 1-20% by weight.

  The content of naphthenic compounds in the base oil, the presence of the desired continuous series of isoparaffins may be measured by field desorption / field ionization (FD / FI) techniques. According to this technique, an oil sample is first separated into a polar (aromatic) phase and a nonpolar (saturated) phase by high performance liquid chromatography (HPLC) method IP 368/01, but pentane instead of hexane as the mobile phase. Is used. Aromatic and saturate fractions are then analyzed using, for example, a Finnigan MAT90 mass spectrometer equipped with an FD / FI interface, and using FI ("soft" ionization technology), the carbon number and hydrogen deficiency perspective To determine the hydrocarbon type.

The type classification of compounds in mass spectrometry is determined by the characteristic ions formed and is usually classified by “Z number”. This is given by the general formula C _n H _{2n + z} for all hydrocarbon species. Since the saturate phase is analyzed separately from the aromatic phase, it is possible to measure different isoparaffin contents with the same stoichiometric ratio or n number. The results from the mass spectrometer are processed using commercially available software (eg, Poly32 available from Sierra Analytics LLC, 3453 Drago Park Drive, Modesto, California GA95350 USA) to determine the relative ratio of each hydrocarbon type. Can do.

  The pour point of the base oil used in the grease formulation according to the present invention may be −5 ° C. or lower, or −10 or −15 ° C. or lower, as measured by ASTM D-4950. It may be, for example, −60 to −10 ° C., preferably −50 to −20 ° C.

  The Fischer-Tropsch derived heavy base oil used in the grease formulation according to the invention is a heavy hydrocarbon product containing at least 95% by weight of paraffin molecules. Preferably such heavy base oils are prepared from Fischer-Tropsch wax and contain greater than 98% by weight saturated paraffinic hydrocarbons. Preferably at least 85%, more preferably at least 90%, even more preferably at least 95%, and most preferably at least 98% by weight of these paraffinic hydrocarbon molecules are isoparaffinic. Preferably at least 85% by weight of the saturated paraffinic hydrocarbon is acyclic hydrocarbon. The naphthenic compound (paraffinic cyclic hydrocarbon) is preferably present in an amount of 15% by weight or less, more preferably less than 10% by weight.

  Heavy base oils are typically liquid at 100 ° C. and at ambient conditions, ie at 25 ° C. and 1 atmosphere (101 kPa).

  It preferably has a viscosity index (ASTM D-2270) of 120 or more, more preferably 130-170.

The VK 100 of the Fischer-Tropsch derived superheavy base oil should be at least 8 mm ² / s. Preferably the VK 100 is at least 10 mm ² / s, more preferably at least 13 mm ² / s, still more preferably at least 15 mm ² / s, Cascade more preferably at least 17 mm ² / s, even more preferably at least 20 mm ² / S. The kinematic viscosity referred to herein may be measured according to ASTM D-445, while the viscosity index (VI) may be measured using ASTM D-2270.

  The Fischer-Tropsch derived heavy base oil preferably has an initial boiling point (IBP) of at least 380 ° C. More preferably the IBP is at least 400 ° C, even more preferably at least 440 ° C. The boiling range distribution of samples having a boiling range above 535 ° C. may be measured according to ASTM D-6352, while for lower boiling materials, the boiling range distribution may be measured according to ASTM D-2887.

  The initial and final boiling point values referred to herein are nominal and refer to the T5 and T95 cut points (boiling temperatures) obtained by gas chromatograph simulated distillation (GCD).

  Since conventional petroleum-derived hydrocarbons and Fischer-Tropsch derived hydrocarbons contain a mixture of components of various molecular weights with a wide range of boiling points, the present disclosure optionally recovers 10% by weight of each boiling range. Reference is made to the point, and the 90 wt% recovery point. The 10 wt% recovery point refers to the temperature at which 10 wt% hydrocarbon present in the cut volatizes at atmospheric pressure and can therefore be recovered. Similarly, the 90 wt% recovery point refers to the temperature at which 90 wt% hydrocarbon present volatilizes at atmospheric pressure. When referring to the boiling range distribution, this specification refers to the boiling range of 10 wt% and 90 wt% recovered boiling points.

The molecular weight referred to herein may be measured according to ASTM D-2503. The Fischer-Tropsch derived heavy base oil preferably contains at least 95% by weight of _{C25 +} hydrocarbon molecules. More preferably it contains at least 75% by weight of C ₃₅₊ hydrocarbon molecules.

  Fischer-Tropsch derived heavy base oils can typically have a cloud point of + 49 ° C to -60 ° C. Preferably it can have a cloud point of + 30 ° C to -55 ° C, more preferably a cloud point of + 10 ° C to -50 ° C. “Cloud point” refers to the temperature at which the base oil begins to become cloudy and may be measured according to ASTM D-5773.

  For bottoms, the pour point of the Fischer-Tropsch derived heavy base oil for a given feed composition and boiling range (defined by the lower cut point from distilled base oil and gas oil fraction after dewaxing) And kinematic viscosity was found to be related to the degree of dewaxing treatment. Fischer-Tropsch derived heavy base oil used in grease formulations according to the present invention may have an even lower pour point, such as less than -8 or -9 ° C, or preferably -30 ° C or less. Thus, in contrast to the relatively mild dewaxing, which results in a pour point of, for example, around −6 ° C., 0-9 ° C., typically undergoes a relatively high (ie high temperature catalyst) dewaxing. “Pour point” refers to the temperature at which a base oil sample begins to flow under carefully controlled conditions. The pour point referred to herein may be measured according to ASTM D-97-93 or D-5950.

  Thus, in the case of a Fischer-Tropsch derived heavy base oil, it may have a pour point of -15 ° C or less, preferably -20 or -25 or -28 or even -30 ° C or less.

  The Fischer-Tropsch derived heavy base oil preferably has a viscosity index of 120-160. It preferably contains no or very little sulfur and nitrogen containing compounds. As mentioned above, this is typical for products derived from the Fischer-Tropsch reaction, using a synthesis gas that is almost free of impurities. Preferably the base oil is sulfur, nitrogen (in the form of hydrocarbon compounds containing them) in an amount of less than 50 ppmw (parts per million by weight), more preferably less than 20 ppmw, and even more preferably less than 10 ppmw. And contains metal. Most preferably it generally contains sulfur and nitrogen at a level below the detection limit, currently 5 ppmw for sulfur and 1 ppmw for nitrogen, for example when using X-ray or Antek nitrogen tests for quantification. However, sulfur may be introduced through the use of hydrosulfide hydrocracking / hydrodewaxing and / or sulfurized catalytic dewaxing catalysts.

  The Fischer-Tropsch derived heavy base oil used in the present invention is preferably separated as a residual fraction from hydrocarbons produced during the Fischer-Tropsch synthesis reaction and subsequent hydrocracking and dewaxing steps.

  More preferably, this fraction is a residual oil containing the highest molecular weight compounds still present in the hydroisomerization process product. The 10% by weight recovery boiling point of the fraction is preferably above 370 ° C, more preferably above 400 ° C, and most preferably above 500 ° C in certain embodiments of the invention.

Fischer-Tropsch derived superheavy base oil (VK 100 is typically 8 or 9 mm ² / s or higher) is further characterized by its different carbon species content. More specifically, it is a repeating methylene carbon that is 4 or more carbons away from the end groups and / or branches compared to the percentage of ε methylene carbon atoms it contains, i.e. the percentage of its isopropyl carbon atoms (further CH ₂ ) (referred to as ₂ > 4). In the following text, the ratio between the percentage of ε methylene carbon atoms and the percentage of isopropyl carbon atoms (ie the carbon atoms in the isopropyl branch) as measured by the base oil as a whole is referred to as the ε: isopropyl ratio.

  The Fischer-Tropsch derived heavy base oil used in the present invention preferably has an alkyl content greater than 10 per 100 carbon atoms in the molecule, as measured according to the method disclosed in US Pat. No. 7,053,254. It has the average branching degree of branches.

The branching properties and carbon composition of a Fischer-Tropsch derived base oil are conveniently determined using ¹³ C-NMR, vapor pressure osmometry (VPO), and field ionization mass spectrometry (FIMS) as follows: This can be determined by analyzing the sample. The average molecular weight is obtained by the vapor pressure osmotic pressure method (VPO). The sample is then characterized at the molecular level by nuclear magnetic resonance (NMR) spectroscopy. Z number and average carbon number were determined by FIMS.

Conventional NMR spectra can have signal overlap problems due to the presence of multiple isomers in the base oil composition. To overcome this problem, selected multi-line subspectral carbon-13 nuclear magnetic resonance ( ^13C -NMR) analysis can be applied. In particular, a synchronized spin echo method (GASPE) can be applied to obtain a quantitative CH _n sub-spectrum. Quantitative data obtained from GASPE has even better accuracy than that obtained from distortion-free enhancement due to polarization transfer (DEPT, such as applied in the method disclosed in US Pat. No. 7,053,254). be able to.

  Based on the average molecular weight obtained by GASPE data and VPO, the average number of branches and aliphatic rings can be calculated. Furthermore, based on GASPE, the distribution of the side chain length and the position of the methyl group along the straight chain are obtained.

All quantitative carbon multiplicity analyzes were usually performed at room temperature. However, this is only true for materials that are liquid under these conditions. This method applies to all Fischer-Tropsch derived or base oil materials that are turbid or waxy solids at room temperature and therefore cannot be analyzed by conventional methods. A suitable method for NMR measurement is as follows. For practical reasons, the maximum measurement temperature is limited to 50 ° C., and deuterated chloroform (CDC ₁₃ ) is used as a measurement solvent for quantitative carbon multiplicity analysis. The base oil sample is heated in a 50 ° C. oven until a clear and liquid homogeneous product is formed. A portion of the sample is then transferred to the NMR tube. Preferably, the NMR tube and any equipment used for sample movement are kept at this temperature. The solvent identified above is then added and the sample is dissolved by shaking the tube, optionally with reheating of the sample. The NMR apparatus is kept at 50 ° C. during data acquisition to prevent any refractory material from solidifying in the sample. Place the sample in the NMR instrument for a minimum of 5 minutes to equilibrate the temperature. Since shim adjustment and tuning both change significantly at high temperatures, the instrument must then be re-shimmed and retuned, and then NMR data can be acquired.

The CH ₃ sub-spectrum is obtained using a GASPE pulse sequence by adding the CSE spectrum (standard spin echo) to 1 / J GASPE (synchronization acquired spin echo). The resulting spectrum contains only primary (CH ₃ ) and tertiary (CH) carbon peaks.

Tabular data is then applied and corrected for chain ends to assign various carbon branched carbon resonances to specific positions and lengths. The sub-spectrum is then incorporated to give quantitative values for the different CH ₃ signals as follows.

1. CH ₃ - carbon a. 25 ppm chemical shift (referenced to TMS).
b. 19 and 21 ppm can be identified as the following general types of methyl branches (see Formula 1):

Formula 1
c. A characteristic strong signal of 22-24 ppm in the region can be clearly identified as an isopropyl end group of the following general structure (see Formula 2):

Formula 2

In this case, one of the methyl carbon atoms is classified as the end of the main chain and the other as a branch. Thus, when calculating the methyl branch content, the intensity of these signals is halved.
d. In addition, some additional weak signals in the 15-19 ppm region are considered to belong to the isopropyl group with an additional branch at the 3 position.
e. Some weak signals in the 8 to 8.5 ppm region observed in the spectrum are likely to be related to 3,3-dimethyl substituted structures (Equation 3):

Formula 3

In this case, the observed signal is that of the terminal CH ₃ but there are two corresponding methyl branches. The total value of these signals is therefore doubled (the signals of the two methyl branches are not counted independently).

The overall estimate of methyl branch content is therefore based on the following calculation (the term “Int” represents the integral, equation 4):
Σ (integrated methyl) = Int 19-20 ppm + (Int 22-25 ppm) / 2 + Int 15-19 ppm + (Int 7.0-9 ppm) * 2
(Formula 4)

  2. The calculation of ethyl branch content is based on evidence from other peak assignments, assuming that the isopentyl end group content is negligible, two characteristic relatively strong observed at 11.5 and 10.9 ppm Based on signal. Thus, the calculation of ethyl branch content is based solely on the integration of the signal from 10 to 11.2 ppm.

3. The overall theoretical terminal CH ₃ content is calculated based on the “Z” content and the average carbon number measured by FIMS. The C ₃₊ branch content is then determined by subtracting the known terminal CH3 content from the theoretical terminal CH3 content, ie half of the isopropyl value, the value of 3-methyl substitution, and the value of 3,3-dimethyl substituted structure. This gives a signal value in the 14 ppm region belonging to CH ₃ at the chain end, the difference being the value of the C ₃₊ branch:
Σ (integral C _{3 +} branch) = Int 14-15 ppm-((theoretical terminal CH ₃ )-(Int 11.2-11.8 ppm)-(Int 22-25 ppm) / 2-Int 7-9 ppm))
(Formula 5)

  In its broadest sense, the present invention provides a grease formulation containing a paraffinic base oil, particularly a heavy base oil, having one or more of the above characteristics, regardless of whether the oil is actually Fischer-Tropsch derived. Includes things.

  The grease formulation according to the invention may also contain two or more Fischer-Tropsch derived base oils, for example a blend of two or more such base oils having a generally desired property, in particular a viscosity. Good.

  A Fischer-Tropsch derived base oil may be the only base oil component in the formulation. Alternatively, it may be used in combination with one or more additional base oil components. The formulation may further contain, for example, a non-Fischer-Tropsch derived base oil or a mixture thereof. Thus, in accordance with the present invention, a Fischer-Tropsch derived base oil may be partially used in a grease formulation instead of a non-Fischer-Tropsch derived base oil, for example to achieve one or more of the advantages described above. . This gives greater flexibility to grease formulation, as well as a wider choice of balancing manufacturing costs against performance.

  Preferred properties of such additional base oil components may be as described above for the Fischer-Tropsch derived base oil. The entire formulation suitably contains less than 40 or 30 or 20% by weight, preferably less than 10 or 5% by weight of such additional base oil components.

Examples of additional base oil components include mineral based paraffinic and naphthenic type base oils such as esters, polyalphaolefins, polyalkylene glycols, and synthetic base oils. Of these, esters can be beneficial to improve the biodegradability of grease formulations. When present, the content of additional ester base oil may be 1-30% by weight, more preferably 5-25% by weight, based on the total formulation. Suitable ester compounds are those which can be derived by reacting an aliphatic mono-, di- and / or polycarboxylic acid with isotridecyl alcohol under esterification conditions. Examples of such compounds include octane-1,8-dioic acid, 2-ethylhexane-1,6 diacid, and isotridecyl ester of dodecane-1,12-dioic acid. Preferably the ester compound is the so-called pentaerythritol tetrafatty acid ester (PET ester) made by esterification with pentaerythritol (PET) branched or linear fatty acids, preferably C ₆ -C ₁₀ acids. Such esters may contain di-PET as an impurity.

  However, it has proved particularly advantageous to use Fischer-Tropsch derived base oils, in particular Fischer-Tropsch derived heavy base oils, as the substantially only base oil component in the grease formulation according to the invention. It was. “Substantially” means in this context 70% or more, preferably 90% or more, most preferably 100% by weight of any base oil component in the formulation of a Fischer-Tropsch derived base oil as described above. Or a paraffinic base oil having at least the preferred characteristics described above.

  The Fischer-Tropsch derived base oil used in the present invention may be produced by any suitable Fischer-Tropsch process. Examples of Fischer-Tropsch methods are the so-called Sasol's commercial Slurry Phase Distilate technology, the Shell Middle Distillate Synthesis method mentioned above, and the “AGC-21” Exxon Mobil method. Regarding these and other methods, for example, EP-A-776959, EP-A-668342, U.S. Pat. No. 4,943,672, U.S. Pat. No. 5,059,299, WO9934917, And in more detail in WO9920720. Typically, these Fischer-Tropsch synthesis products contain hydrocarbons having 1 to 100, or even more than 100, carbon atoms.

  If the base oil is one of the desired isoparaffinic products of the Fischer-Tropsch process, it may be advantageous to use a relatively heavy Fischer-Tropsch derived feed. Such a feed suitably contains at least 30%, preferably at least 50%, more preferably at least 55% by weight of the compound having at least 30 carbon atoms. Furthermore, the weight ratio of the compound having at least 60 carbon atoms to that having at least 30 carbon atoms in the feed is preferably at least 0.2, more preferably at least 0.4, most preferably at least 0.55. If the feed has a 10 wt% recovery boiling point above 500 ° C, the wax content is preferably above 50 wt%.

Preferably the Fischer-Tropsch derived feed has an ASF-α value (Anderson-Schulz-Flory) of at least 0.925, preferably at least 0.935, more preferably at least 0.945, and even more preferably at least 0.955. C ₂₀₊ fraction having a chain growth factor). Such a Fischer-Tropsch derived feed can be obtained by any method that yields a suitably heavy product as described above.

  In general terms, the production of Fischer-Tropsch derived base oil involves a Fischer-Tropsch synthesis, a hydroisomerization process, and an optional pour point reduction process. Fischer-Tropsch synthesis can be performed on syngas prepared from all types of hydrocarbonaceous materials such as coal, natural gas, or biological materials such as wood and hay. Hydroisomerization converts n-paraffins to isoparaffins, thus increasing the degree of branching in the hydrocarbon molecules and improving cold flow characteristics. Depending on the catalyst used and the isomerization conditions, this process can result in long chain hydrocarbon molecules with relatively highly branched end regions, such molecules tend to exhibit particularly good cold flow performance. is there.

The hydroisomerization and optional pour point reduction steps may be performed by:
(A) hydrocracking / hydroisomerizing a Fischer-Tropsch product such as the feed described above;
(B) isolating in particular the base oil or base oil intermediate fraction from the product of step (a).

  If the viscosity and / or pour point of the base oil obtained in step (b) is as desired, no further processing is necessary and the oil can be used directly in the formulations according to the invention. However, if required, the pour point of the base oil intermediate fraction may be further reduced in step (c) by solvent or more preferably by catalytic dewaxing.

  The desired viscosity of the base oil may be obtained by isolating (by distillation) a product having a suitable boiling range and corresponding viscosity from the intermediate base oil fraction or from the dewaxed oil. The distillation may be a vacuum distillation process.

  The hydroconversion / hydroisomerization reaction of step (a) is preferably carried out in the presence of hydrogen and a catalyst, which catalyst can be selected from those known to those skilled in the art, examples of which are described in more detail below. It is stated in. The catalyst can in principle be any catalyst known in the art to be suitable for the isomerization of paraffinic molecules. Generally suitable hydroconversion / hydroisomerization catalysts are on refractory oxide carriers such as amorphous silica alumina (ASA), alumina, fluorinated alumina, molecular sieves (zeolite) or mixtures of two or more thereof. Including a hydrogenation component carried on the substrate.

  Preferred catalysts for use in the hydroconversion / hydroisomerization step (a) include those containing platinum and / or palladium as the hydrogenation component. A highly preferred hydroconversion / hydroisomerization catalyst comprises platinum and palladium supported on an amorphous silica-alumina (ASA) carrier. Platinum and / or palladium is preferably present as an element in an amount of 0.1 to 5.0% by weight, more preferably 0.2 to 2.0% by weight, calculated on the basis of the total carrier weight. To do. When both elements are present, the weight ratio of platinum to palladium may vary within a wide range, but is preferably in the range of 0.05 to 10, more preferably 0.1 to 5. Examples of suitable noble metals on ASA catalysts are disclosed, for example, in WO 9410264 and EP-A-0582347. Other suitable noble metal based catalysts such as platinum on a fluorinated alumina carrier are disclosed, for example, in US Pat. No. 5,059,299 and WO 9220759.

  A second type of suitable hydroconversion / hydroisomerization catalyst includes, as a hydrogenation component, at least one Group VIB metal, preferably tungsten and / or molybdenum, and preferably nickel and / or And those containing at least one non-noble Group VIII metal that is cobalt. One or both metals may be present as oxides, sulfides or combinations thereof. The Group VIB metal is preferably present in an amount of 1-35 wt%, more preferably 5-30 wt%, based on the total carrier weight. The Group VIII non-noble metal is suitably present in an amount of 1-25% by weight, preferably 2-15% by weight, calculated on the total carrier weight. This type of hydroconversion catalyst which has been found to be particularly suitable is one comprising nickel and tungsten supported on fluorinated alumina.

  The above non-noble metal based catalysts are preferably used in their sulfurized form. In order to maintain the sulfurized form of the catalyst during use, some sulfur must be present in the feed, such as at least 10 mg / kg or more preferably 50-150 mg / kg sulfur.

Preferred catalysts that can be used in the non-sulfurized form include a Group VIII non-noble metal such as iron or nickel supported on an acidic support in combination with a Group IB metal such as copper. Copper is preferably present to inhibit the hydrocracking of paraffin to methane. The catalyst preferably has a pore volume in the range of 0.35 to 1.10 ml / g as measured by water absorption, a surface area of 200 to 500 m ² / g as measured by BET nitrogen adsorption and a bulk of 0.4 to 1.0 g / ml Has a density. The catalyst support is preferably made of amorphous silica-alumina, which may be present in the range of 5 to 96% by weight, preferably 20 to 85% by weight. The silica content of the support such as SiO ₂ is preferably 15 to 80% by weight. The support may also contain small amounts of binders such as 20-30% by weight of alumina, silica, Group IVA metal oxides, viscosity, magnesia, etc., preferably alumina or silica.

  For the preparation of amorphous silica-alumina microspheres, see Ryland, Lloyd B. et al. , Tamale, M .; W. and Wilson, J .; N. , In “Cracing Catalysts”, Catalysis: Volume VII, Ed. Paul H. Emmett, Reinhold Publishing Corporation, New York, 1960, 5-9.

  The catalyst may be prepared by co-impregnation of the metal from solution onto the support, drying at 100-150 ° C., and calcination in air at 200-550 ° C. Group VIII metals are usually present in lower amounts, whereas Group VIII metals may be present in amounts up to about 15% by weight, preferably 1-12% by weight. For example, the weight ratio of the Group IB metal to the Group VIII metal may be about 1: 2 to about 1:20.

Typical catalyst specifications are defined below.
Ni: 2.5 to 3.5% by weight
Cu: 0.25 to 0.35% by weight
Al ₂ O _{3 to} SiO ₂ : 65 to 75% by weight
Al ₂ O ₃ (binder): 25 to 30% by weight
Surface area: 290-325 m ² / g
Pore volume: (Hg) 0.35 to 0.45 ml / g
Bulk density: 0.58 to 0.68 g / ml

  Another class of suitable hydroconversion / hydroisomerization catalysts include molecular sieve types, suitably comprising at least one Group VIII metal component, preferably Pt and / or Pd, as the hydrogenation component. Material-based ones can be mentioned. Suitable zeolites and other aluminosilicate materials include zeolite β, zeolite γ, ultrastable γ, ZSM-5, ZSM-12, ZSM-22, ZSM-23, ZSM-48, MCM-68, ZSM-35. , SSZ-32, ferrierite, mordenite, and silica-aluminophosphates such as SAPO-11 and SAPO-31. Examples of suitable hydroconversion / hydroisomerization catalysts are described, for example, in WO 9201657. Combinations of these catalysts are also possible.

  A suitable hydroconversion / hydroisomerization process includes a first step in which a zeolite β or ZSM-48 based catalyst is used, and ZSM-5, ZSM-12, ZSM-22, ZSM-23, ZSM- 48, with MCM-68, ZSM-35, SSZ-32, ferrierite or mordenite based catalysts being used. Among the latter group, ZSM-23, ZSM-22, and ZSM-48 are preferred. An example of such a process is described in U.S. Patent Application Publication No. 20040065581, a first step catalyst comprising platinum and zeolite beta, and a second step comprising platinum and ZSM-48. The use of a catalyst is disclosed.

  Among them, the Fischer-Tropsch product was first subjected to a first hydroisomerization process using an amorphous catalyst containing a silica-alumina carrier as described above, using a catalyst containing a molecular sieve. A combination of methods followed by a second hydroisomerization step has also been identified as a preferred method of preparing the base oil used in the present invention. Preferably, the first and second hydroisomerization steps are performed in series flow. More preferably the two steps are carried out in a single reactor comprising the above amorphous and / or crystalline catalyst bed.

  In step (a), the Fischer-Tropsch feed is contacted with hydrogen in the presence of a catalyst under high temperature and pressure. The temperature is typically in the range of 175-380 ° C, preferably higher than 250 ° C, more preferably 300-370 ° C. The pressure is typically in the range of 10 to 250 bar, preferably 20 to 80 bar. Hydrogen may be supplied at a gas hourly space velocity of 100 to 10000 Nl / l / hr, preferably 500 to 5000 Nl / l / hr. The hydrocarbon feed may be provided at a weight space hourly speed of 0.1-5 kg / l / hr, preferably higher than 0.5 kg / l / hr, more preferably lower than 2 kg / l / hr. The ratio of hydrogen to hydrocarbon feed may be in the range of 100-5000 Nl / kg, preferably 250-2500 Nl / kg.

  The conversion in step (a), preferably defined as the weight percentage per pass, where the feed with a boiling point higher than 370 ° C. reacts to a fraction with a boiling point lower than 370 ° C. is preferably at least 20 % By weight, preferably at least 25% by weight, but preferably not more than 80% by weight, more preferably not more than 65 or 70% by weight. The feeds used in the above definition are all hydrocarbon feeds fed to step (a) and thus any arbitrary, eg from high boiling fractions that may be obtained in step (b) Optional recycle to step (a).

  In step (b), the product of step (a) is separated into one or more distillate fuel fractions and base oil or base oil precursor fractions, preferably having the desired viscosity. If the pour point or precursor of the base oil is not in the desired range, it may be further reduced by a dewaxing step (c), preferably by catalytic dewaxing. In such embodiments, it may be a further advantage to dewax a wider boiling fraction of the product of step (a). From the resulting dewaxed product, the desired base oil having the desired viscosity and optionally other oils can then be isolated, for example by distillation. Dewaxing is preferably described, for example, in WO 02070627, which is hereby incorporated by reference (see particularly page 8 line 27 to page 11 line 6 for examples of suitable dewaxing conditions and catalysts). And is carried out by catalytic dewaxing as described in more detail below. If desired, the final boiling point of the feed to the dewaxing step (c) may be less than or equal to the final boiling point of the product of step (a).

  Prior to use in the formulation according to the invention, for example after dewaxing step (c), the base oil is described, for example, on page 11 line 7 to page 12 line 12 of WO 02070627. One or more further treatments such as hydrofinishing may be applied.

  Suitable general methods for the production of Fischer-Tropsch derived base oils are described, for example, in WO020070627. For other suitable production methods for heavy and ultra-heavy Fischer-Tropsch derived base oils, see WO2004403607, US Pat. No. 7,053,254, EP-A-1366134, EP-A-1382639. No., EP-A-1516038, EP-A-1534801, WO2004003113, and WO20055063941.

  In order to prepare the paraffinic superheavy base oil used in the present invention, the Fischer-Tropsch derived bottoms is preferably subjected to isomerization. This converts n-paraffins to isoparaffins, thus increasing the degree of branching in the hydrocarbon molecules and improving cold flow characteristics. Depending on the catalyst used and the isomerization conditions, this can result in long chain hydrocarbon molecules having relatively highly branched end regions. Such molecules tend to exhibit relatively good cold flow performance.

  The isomerized bottoms may be subjected to further downstream processing such as hydrocracking, hydrotreating and / or hydrofinishing. This is preferably subjected to a dewaxing step which further reduces its pour point, either as described above, either by solvent or more preferably by catalytic dewaxing.

The Fischer-Tropsch derived superheavy base oil used in the grease formulation according to the invention is preferably a heavy canned distillation fraction obtained from a Fischer-Tropsch derived wax or waxy raffinate feed by:
(A) hydrocracking / hydroisomerizing a Fischer-Tropsch derived feed in which at least 20% by weight of the compound has at least 30 carbon atoms;
(B) separating the product of step (a) into one or more distillation fractions and a residual heavy fraction comprising at least 10% by weight of a compound having a boiling point above 540 ° C .;
(C) subjecting the residual fraction to catalytic pour point reduction;
(D) isolating a Fischer-Tropsch derived paraffinic heavy base oil component from the eluate of step (c) as a residual heavy fraction.

  In addition to isomerization and fractionation, Fischer-Tropsch derived product fractions may also be subjected to various other operations such as hydrocracking, hydrotreating and / or hydrofinishing.

  The feed from step (a) is a Fischer-Tropsch derived product. The initial boiling point may be up to 400 ° C, but is preferably less than 200 ° C. Preferably, any compound having 4 or fewer carbon atoms, and any compound having a boiling point in that range, is separated from the Fischer-Tropsch synthesis product before the Fischer-Tropsch synthesis product is used in the hydroisomerization step. Is done. Examples of suitable Fischer-Tropsch methods are described in WO 9934917 and AU-A-698391. The disclosed method produces a Fischer-Tropsch product as described above.

  Fischer-Tropsch products obtained directly from the Fischer-Tropsch process usually contain a waxy fraction that is solid at room temperature.

  Again, the hydrocracking / hydroisomerization reaction of step (a) is preferably carried out in the presence of hydrogen and a catalyst, for example a catalyst of the type mentioned above. The catalyst used in hydroisomerization typically includes an acidic functional group and a hydrogenation-dehydrogenation functional group. A preferred acidic functional group is a refractory metal oxide carrier. Suitable carrier materials include silica, alumina, silica-alumina, zirconia, titania, and mixtures thereof. Preferred support materials included in the catalyst are silica, alumina, and silica-alumina. A particularly preferred catalyst comprises platinum supported on a silica-alumina carrier. For example, the use of a catalyst containing a halogen compound such as fluorine requires special operating conditions and can involve environmental problems, so preferably such a catalyst does not contain a halogen compound. For examples of suitable hydrocracking / hydroisomerization processes and catalysts, see WO0014179, EP-A-532118, EP-A-666894, and the EP- A-776959.

  Preferred hydrogenation-dehydrogenation functional groups are Group VIII metals such as, for example, cobalt, nickel, palladium, and platinum, more preferably platinum. In the case of platinum and palladium, the catalyst comprises a hydrogenation-dehydrogenation active component in an amount of 0.005 to 5 parts by weight, preferably 0.02 to 2 parts by weight per 100 parts by weight of support material. Also good. When nickel is used, there is typically a higher content, optionally using nickel in combination with copper. Particularly preferred catalysts used in the hydroconversion stage comprise platinum in an amount ranging from 0.05 to 2 parts by weight, more preferably from 0.1 to 1 part by weight per 100 parts by weight of support material. The catalyst also includes a binder to enhance catalyst strength. The binder can be non-acidic. Examples are clay and other binders known to those skilled in the art.

  Other features of the hydroisomerization step (a) may be as described above.

  The product of the hydroisomerization process preferably contains at least 50% by weight, more preferably at least 60% by weight, even more preferably at least 70% by weight isoparaffins, the remainder from n-paraffins and naphthenic compounds. Composed.

  In step (b), the product of step (a) is divided into one or more distillation fractions, the residual heavy fraction comprising at least 10% by weight of compound having a boiling point above 540 ° C. This is advantageously performed by performing one or more distillate separations on the hydroisomerization process effluent to produce at least one middle distillate fuel fraction and the residual fraction used in step (c). And is done.

  Preferably, the eluate from step (a) is first subjected to atmospheric distillation. Residue as obtained from such distillation may be subjected to further distillation carried out in near vacuum conditions in certain preferred embodiments, resulting in a fraction having a higher 10 wt% recovery boiling point. It is done. The 10 wt% recovery boiling point of the residual liquid may preferably vary between 350 and 550 ° C. At least 95% by weight of this atmospheric pressure bottoms or residual liquid will boil above 370 ° C.

  This fraction may be used directly in step (c) or may be subjected to an additional vacuum distillation, preferably carried out at a pressure of 0.001 to 0.1 bar. The feed of step (c) is preferably obtained as the bottoms of such a vacuum distillation.

  In the step (c), a catalytic pour point lowering step is performed on the heavy residual fraction obtained in the step (b). Step (c) may be carried out using any hydroconversion process that can reduce the wax content to less than 50% by weight of its original value. The wax content of the intermediate product is preferably less than 35% by weight, more preferably 5 to 35% by weight, even more preferably 10 to 35% by weight. The product as obtained in step (c) preferably has a freezing point of less than 80 ° C. Preferably, the intermediate product above 50% by weight, more preferably above 70% by weight boils above the 10% recovery point of the wax feed used in step (a).

  The wax content may be measured according to the following procedure. One part by weight of the oil fraction under analysis is diluted with 4 parts of a mixture of methyl ethyl ketone and toluene (50/50 vol / vol), which is subsequently cooled to −20 ° C. in a refrigerator. The mixture is subsequently filtered at -20 ° C. The wax is thoroughly washed with cold solvent, removed from the filter, dried and weighed. When referring to oil, the weight% value means 100% minus the weight percentage of the wax content.

  A possible method of step (c) is the hydroisomerization method as described above for step (a). It has been found that such a catalyst may be used to reduce the wax level to a desired level. By varying the degree of working conditions as described above, those skilled in the art can easily determine the operating conditions required to obtain the desired wax conversion. However, in order to optimize the oil yield, a temperature of 300-330 ° C. and 0.1-5 kg of oil (kg / l / hr) per liter of catalyst per hour, more preferably 0.1-3 Especially preferred is a space-time per hour.

  A more preferred class of catalysts that may be applied in step (c) are dewaxing catalysts. The operating conditions applied when using such a catalyst should be such that the wax content remains in the oil. In contrast, typical catalytic dewaxing processes attempt to reduce the wax content to near zero. The use of a dewaxing catalyst that includes molecular sieves allows more heavy molecules to be retained in the dewaxed oil. A more viscous base oil can then be obtained.

  The dewaxing catalyst that may be applied in step (c) suitably comprises a molecular sieve as described above, optionally in combination with a metal having a hydrogenation function, such as, for example, a Group VIII metal. Molecular sieves, more preferably molecular sieves having a pore size of 0.35 to 0.8 nm, exhibit good catalytic capacity and reduce the wax content of the wax feed. Suitable zeolites are mordenite, beta, ZSM-5, ZSM-12, ZSM-22, ZSM-23, SSZ-32, ZSM-35, ZSM-48, and combinations of said zeolites, among which ZSM -12 and ZSM-48 are most preferred. Another preferred group of molecular sieves are silica-alumina phosphate (SAPO) materials, of which SAPO-11 is most preferred, as described, for example, in US Pat. No. 4,859,311. ZSM-5 may optionally be used in its HZSM-5 form in the absence of a Group VIII metal. Other molecular sieves are preferably used in combination with added Group VIII metals. Preferred Group VIII metals are nickel, cobalt, platinum, and palladium. Examples of possible combinations are Pt / ZSM-35, Ni / ZSM-5, Pt / ZSM-23, Pd / ZSM-23, Pt / ZSM-48, and Pt / SAPO-11, or Pt / SAPO in a laminated structure Zeolite β and Pt / ZSM-23, Pt / Zeolite β and Pt / ZSM-48, or Pt / Zeolite β and Pt / ZSM-22. For further details and examples of suitable molecular sieves and dewaxing conditions, see, for example, WO 97718278, US Pat. No. 4,343,692, US Pat. No. 5,053,373, US Pat. No. 5,252,527, US Pat. This is described in published application 20040065581, U.S. Pat. No. 4,574,043, and EP-A-1029029.

  Another preferred class of molecular sieves are those with relatively low isomerization selectivity and high wax conversion selectivity, such as ZSM-5 and ferrierite (ZSM-35).

  The dewaxing catalyst preferably also includes a binder. The binder can be a synthetic or natural (inorganic) material such as clay, silica and / or metal oxides. Natural clays are, for example, montmorillonite and kaolin systems. The binder is preferably a porous binder material such as a refractory oxide, examples of which include alumina, silica-alumina, silica-magnesia, silica-zirconia, silica-tria, silica-beryllia, and silica-titania, And ternary compositions such as silica-alumina-tria, silica-alumina-zirconia, silica-alumina-magnesia and silica-magnesia-zirconia. More preferably, a low acidity refractory oxide binder material that is essentially free of alumina is used. Examples of these binder materials are silica, zirconia, titanium dioxide, germanium dioxide, boria, and mixtures of two or more of those listed above. The most preferred binder is silica.

  A preferred class of dewaxing catalyst comprises an intermediate zeolite crystallite as described above and a low acidity refractory oxide binder material essentially free of alumina as described above, wherein the aluminosilicate zeolite crystallites The surface is modified by subjecting the aluminosilicate zeolite microcrystals to a surface dealumination treatment. A preferred dealumination treatment involves contacting the binder and zeolite extrudates with an aqueous solution of fluorosilicate, as described, for example, in US Pat. No. 5,157,191 or WO002951111. Examples of suitable dewaxing catalysts as described above are silica bonded and dealuminated Pt / ZSM-5, as described, for example, in WO0029511 and EP-B-832171, Or Pt / ZSM-35 that is silica bonded and dealuminated.

  If a dewaxing catalyst is used, the conditions of step (c) are typically accompanied by an operating temperature that is in the range of 200-500 ° C, preferably 250-400 ° C. Preferably the temperature is 300-330 ° C. The hydrogen pressure may range from 10 to 200 bar, preferably 40 to 70 bar. Weight space hourly speed (WHSV) may range from 0.1 to 10 kg of oil (kg / l / hr) per liter of catalyst per hour, preferably 0.1 to 5 kg / l / hr, more preferably Is 0.1 to 3 kg / l / hr. The ratio of hydrogen to oil may range from 100 to 2,000 liters of hydrogen per liter of oil.

  In step (d), the product of step (c) is typically sent to a vacuum column where various distillate base oil cuts are collected. These distilled base oil fractions may be used to prepare lubricating base oil formulations or they may be broken down into lower boiling products such as diesel or naphtha. The residue collected from the vacuum column contains a mixture of high boiling hydrocarbons and can be used to prepare the heavy base oil used in the present invention.

  Further, the product obtained in step (c) may be subjected to additional treatment such as solvent dewaxing. The product is contacted with activated carbon, for example in a clay treatment step or to improve its stability, as described, for example, in US Pat. No. 4,795,546 and EP-A-712922. Can be further processed.

  The thickener contained in the grease formulation according to the present invention may be a soap or a non-soap thickener.

  Examples of suitable non-soap thickeners include urea compounds, which are compounds containing a urea group (—NHCONH—) in the molecular structure. These compounds include mono-, di-, tri-, tetra-, and polyurea compounds depending on the number of urea bonds they contain. Other suitable non-soap thickeners include, among others, bentonite, attapulgite, hectorite, illite, saponite, oleagite, treated with ammonium compounds that make them hydrophobic (eg, tetra-alkylammonium halides). Clays such as biotite, meteorite, zeolite clay; silica gels; polymeric thickeners such as PTFE (polytetrafluoroethane) or hydrocarbon polymers such as polypropylene or polymethylpentene; carbon blacks; and mixtures thereof .

  The thickener may in particular be a soap-based thickener, typically a fatty acid metal salt or a fatty acid mixture metal salt or possibly other fatty metal salts. The soap may be, for example, an alkali metal salt such as sodium, potassium or lithium salt, or an alkaline earth metal salt such as calcium, barium or magnesium salt, or aluminum salt. It may be selected from lithium, sodium, calcium, and aluminum soaps, including mixed salts such as lithium / calcium soaps. It may in particular be a lithium or calcium salt, especially a lithium salt.

Soaps may be formed by mixing bases such as metal hydroxides, metal oxides, metal carbonates or other such suitable compounds with a suitable hydrophobic component such as in particular fatty acids or mixtures thereof. Good. The fat component of the soap typically has a carbon chain length of _C6-30 or _C12-30 , preferably _C6-24 or _C12-24 , more preferably _C12-20 . If it is a fatty acid, it may contain other functional groups in addition to the carboxylic acid group, in particular a hydroxyl group such as 12-hydroxyoctadecanoic acid. Examples of suitable fatty acids include stearic acid, hydroxystearic acid, oleic acid, palmitic acid, myristic acid, cottonseed oil acid, and hydrogenated fish oil acid.

  For example, lithium soap thickening grease has been known for many years. Typically lithium soaps are derived from C10-24, preferably C15-18 saturated or unsaturated fatty acids or their derivatives. One such derivative is hydrogenated castor oil, which is a glyceride of 12-hydroxystearic acid, a particularly preferred fatty acid in this context.

  Soap thickeners are generally low to medium molecular weight acids or dibasic acids or salts thereof, such as fatty acid metal salts or mixtures thereof and metal borates such as benzoic acid, boric acid, or lithium borate. It may be a metal complex soap containing an additional complexing agent that is one of the following. The metal and fatty acid components may be as described above. The lower molecular weight acid may be a mono-, di- or polycarboxylic acid, or it may be an inorganic acid such as boric acid. It may be used in the form of an acid salt such as lithium borate. The carboxylic acid may be aromatic or aliphatic, and it may contain other functional groups in addition to the carboxylic acid group. In particular, the metal complex soap may be selected from lithium complexes, calcium complexes, aluminum complexes, and calcium sulfonate complex soaps, and mixtures thereof.

  Complex thickeners with potential use in grease formulations according to the invention include, for example, calcium stearate-acetic acid (see US Pat. No. 2,197,263), barium stearate-acetic acid (US Pat. No. 2,564,561). ), Calcium stearate-caprylic acid-acetic acid complexes (US Pat. No. 2,999,066), and salts of low, medium and high molecular weight acids and nut oil acids.

  Other thickening agents that may be useful in the formulations according to the present invention include US Pat. No. 5,650,380, WO9999014292, US Pat. No. 6,642,187, and US Pat. No. 5,612,297. And those disclosed in Japanese.

  The grease formulation according to the present invention may contain two or more thickeners.

  The formulation preferably contains a relatively high thickener concentration to correct for the low polarity of the Fischer-Tropsch derived base oil. It may contain, for example, thickeners that are 4% by weight or more, or 5 or 10 or 15 or 20 or 21 or 22% by weight or more, based on the total formulation. It may contain up to 20 or 30 or 35 or 40% by weight of thickener. A suitable thickener concentration may be in the range of 5 to 35% by weight, for example 5 to 25% by weight. The thickener concentration depends on the overall consistency required for the formulation.

  For a given Fischer-Tropsch derived base oil, the grease formulation according to the present invention has a higher concentration than is present in grease formulations containing the same amount of mineral-derived base oil having the same viscosity. You may contain a thickener.

  Similarly, the concentration of Fischer-Tropsch derived base oil in the formulation according to the invention may be, for example, 50% by weight or more, or 60 or 70 or 75% by weight or more, based on the total formulation. The formulation may contain a base oil that is up to 80 or 90 or 95% or even 96% by weight. A suitable base oil concentration may be in the range of 60-95 wt%, such as, for example, 75-95 wt%. Again, this depends on the required consistency, and higher base oil concentrations such as about 95% by weight result in a dilute semi-fluid grease, eg lower concentrations such as 75% by weight or less This produces a high consistency, low permeability grease.

  For example, if the Fischer-Tropsch derived base oil is only one of two or more base oils present in the formulation, the concentration of the Fischer-Tropsch derived oil in the entire formulation is 15 or 20% by weight, For example, it may be up to 30 or 40 or 50 or 60% by weight.

  The grease formulation according to the present invention suitably exhibits a permeability of 220-340, preferably 250-310 or 265-295 (e.g. according to standard test method ASTM D-217).

  It is preferably lead free.

  The grease formulation ideally exhibits a suitable level of mechanical stability so that it does not become too thin during application and easily removed from the area intended for lubrication. Mechanical stability may be assessed by stability tests such as admixture stability and roll stability, which measure the consistency or permeability of grease formulations before and after being subjected to rheological stress, ideally In some cases, the grease permeability should change only slightly after such treatment. For example, in a penetration stability test after 100,000 strokes in a grease blender, according to ASTM D-217, the penetration value of the grease formulation is preferably less than 30 points, more preferably 25 or 20 or 15 or 10 Or change less than 5 points. Smaller changes in penetration values in this test suggest greater mechanical stability.

  The grease formulation according to the invention preferably exhibits stability at high temperatures and oxidizing conditions. This may be evaluated, for example, by an oxidation test that measures oxygen uptake at 99 ° C. for over 100 hours. For example, in the Norma Hoffmann “bomb” oxidation test for grease according to ASTM D-942, the pressure drop of the grease formulation according to the invention is preferably not more than 35 kilopascals after 100 hours, more preferably 30 or 25 or Less than 20 kilopascals. A smaller pressure drop in this test suggests greater oxidative stability.

  The formulation is advantageously light in color (eg, white to light beige), making it more comfortable to use in a variety of applications where contamination from darker greases can be a problem. Since Fischer-Tropsch derived base oils generally tend to exhibit lighter colors than their mineral-derived counterparts and less uneven color than conventional mineral oils, the present invention can provide additional advantages in this context. Even in the presence of additives, grease formulations according to the invention are typically lighter in color than similar formulations based on mineral oil. In addition, the reduction in additive levels made possible by the present invention can also help reduce the color unevenness by reducing the overall color of the grease formulation.

  Accordingly, the grease formulation according to the present invention is preferably 0 to 1.5 (colorless ("water white") to light beige), preferably 0 to 1 or 0 to 0, as evaluated according to ASTM D-1500. May have a color scale color of .5. The Fischer-Tropsch derived base oil used in the formulation also suitably has an ASTM D-1500 color of 0 to 1.5, preferably 0 to 1 or 0 to 0.5. Conventional mineral oil based greases, especially those containing additives, are typically much darker and have ASTM D-1500 values of 1 (possibly) 7 (dark brown).

  The grease formulation according to the invention preferably also exhibits good lubricant properties such as wear resistance, extreme pressure properties and anti-fretting properties. Such characteristics may be evaluated using dedicated test methods such as a four-ball wear test, a four-ball extreme pressure (EP) test (fusion load), and a Fafnir fretting test. For example, in a four-ball wear test according to ASTM D-2266 or IP 239, the grease formulation according to the present invention preferably produces a wear scar diameter of 0.6 or 0.5 mm or less, the smaller diameter in such a test being Suggests improved wear resistance. Furthermore, in a four ball EP test according to ASTM D-2596, the grease formulation according to the invention preferably produces a fusion load of 250 kg or more, suggesting good extreme pressure characteristics. Furthermore, in a Fafnir fretting test according to ASTM D-4170, the grease formulation according to the invention preferably results in a wear of less than 10 mg, suggesting good anti-fretting properties.

  The formulation may contain other components in addition to the Fischer-Tropsch derived base oil and thickener. It contains, for example, additives, oxidation resistance (antioxidant additive), corrosion resistance on copper base metal (copper corrosion additive), resistance to rust due to water action on steel (rust inhibitor) Wear resistance and extreme pressure properties (eg antiwear additives), friction characteristics, fretting characteristics, high temperature resistance and / or adhesion or tack may be enhanced. The nature and amount of any such additive will depend on the intended use of the formulation and the properties and performance essential to the formulation.

  Unless otherwise noted, the concentration of each such additional component in the grease formulation is, for example, 0.01 to 10% by weight or 0.01 to 5 or 4 or 3 or 2 or 1 or 0.5% by weight. %, Preferably up to 10% by weight. The total additive content in the formulation may suitably be 1-10% by weight, preferably less than 5% by weight. (All additive concentrations mentioned herein are active substance concentrations based on mass unless otherwise noted. Furthermore, all concentrations are expressed as a percentage of the total grease formulation unless otherwise noted. Stated).

  To prepare a grease formulation according to the invention, one or more additive components such as those listed above are optionally mixed together (preferably with a suitable diluent) into the additive concentrate. The additive concentrate may then be dispersed in the base oil or base oil / thickener mixture.

  Although some were totally unexpected, because of the beneficial effects of incorporating a Fischer-Tropsch derived base oil, the grease formulation according to the present invention is made up of other more conventional, especially mineral oil based grease formulations. It may contain lower levels of additives than the product. Formulations according to the invention are for example 50,000 ppmw or less, in some cases 40,000 or 30,000 or 20,000 or 10,000 ppmw or even 5,000 or 2,000 or even 1,000 ppmw or less An additive may be contained. In one embodiment, the formulation contains substantially no additive (meaning that it contains less than 100 ppmw additive), ideally no additive.

  In particular, the formulation may contain low levels or preferably no antiwear additives in the context of the fourth aspect of the invention, as described below. Thus, for example, the formulation may contain antiwear additives that are less than 2% by weight, preferably less than 1% by weight or even less than 0.5% by weight. In some cases, it may not contain any antiwear additives.

  Similarly, the formulation may contain a low level or preferably no copper corrosion additive in the context of the fifth aspect of the invention, as described below. Thus, for example, the formulation may contain less than 0.3 or 0.2 wt% copper corrosion additive, preferably less than 0.1 or 0.05 wt%. In some cases, it may not contain any copper corrosion additives.

  The formulation may contain low levels or preferably no antioxidant additives in the context of the sixth aspect of the invention, as described below. Thus, for example, it may contain less than 1% by weight, preferably less than 0.5 or 0.3% by weight of antioxidant additives. In some cases it may not contain any antioxidant additives.

  The formulation may contain low levels or preferably no viscosity modifying additives in the context of the seventh aspect of the invention, as described below. For example, it may contain less than 1 wt.%, Preferably less than 0.5 or 0.1 wt. In some cases, it may not contain any viscosity modifying additives.

  The formulation may contain low levels or preferably no cold flow additive (eg, pour point depressant) in the context of the eighth aspect of the invention, as described below. Thus, for example, it may contain less than 0.5% by weight, preferably less than 0.1 or 0.05% by weight of cold flow additives, in particular pour point depressants. In some cases, it may not contain any cold flow additives.

  In accordance with a second aspect of the present invention, the use of a Fischer-Tropsch derived base oil in a grease formulation is provided for the purpose of improving the antiwear performance of the formulation.

  The anti-wear performance of a grease formulation can be evaluated using standard test methods such as ASTM D-2596, IP 239, DIN 51350 or similar techniques, for example using a wear test such as a four ball wear test.

  In general, the improvement in anti-wear performance is manifested by a reduction in wear scars (which may be a reduction in scar volume and / or depth) on two relatively moving components whose surfaces are covered with a test grease formulation. May be used. Thus, in tests such as, for example, a four-ball wear test, a decrease in wear scar diameter on the surface of a stationary sphere after a predetermined time suggests better anti-wear performance. Improvements in wear resistance performance may be manifested by an increase in the usable life of the equipment in which the grease formulation is used and lubricated, and / or by a reduction in wear or similar damage between the relative moving parts of the equipment. Good.

  Improved wear resistance performance is manifested instead or in addition, for example, by reduced fretting in standard test method ASTM D-4170 and / or by improved performance of bearing leak tests such as ASTM D-1263 May be.

  In the context of the second aspect of the invention, the “improvement” of the anti-wear performance of a grease formulation is compared to the performance of the formulation prior to incorporating a Fischer-Tropsch derived base oil, or a non-Fischer-Tropsch derived base oil. Includes any degree of improvement compared to other formulations that contain otherwise. This may involve, for example, adjusting the antiwear performance of the formulation with a Fischer-Tropsch derived base oil to achieve the desired goal.

  A grease formulation prepared in accordance with the present invention is preferably less than 0.8 mm after 1 hour at 40 kg applied load (top ball rotates at 1300 rpm and operating temperature is 75 ° C.) in a four-ball wear test. Results in wear scar diameter. This may result in a wear scar diameter of 0.7 or 0.6 or 0.5 or 0.4 mm or less under the test conditions described above. Preferably this produces such a result, as described above, in the absence of antiwear additives or at least in the presence of only such low levels.

  According to a third aspect of the present invention, there is provided the use of a Fischer-Tropsch derived base oil in a grease formulation for the purpose of improving the copper corrosion performance of the formulation.

  The copper corrosion performance of a grease formulation is a measure of the speed with which color develops on the copper surface with which it comes into contact and is typically measured at elevated temperatures such as 100 ° C. for hours or days. It may be evaluated, for example, using standard test method ASTM D-130, or similar techniques. The improvement in copper corrosion performance is reduced under these conditions, preferably over 3 or 5 or 10 hours, or over 12 or 24 hours, with less color on the copper surface exposed to the grease formulation. It may be manifested by.

  In the context of the third aspect of the invention, the “improvement” of the copper corrosion performance of the grease formulation is compared to the performance of the formulation prior to incorporating a Fischer-Tropsch derived base oil or a non-Fischer-Tropsch derived base oil. Includes any degree of improvement compared to other formulations that contain otherwise. This may involve, for example, adjusting the copper corrosion performance of the formulation with a Fischer-Tropsch derived base oil to achieve the desired goal.

  Grease formulations prepared in accordance with the present invention preferably produce a copper corrosion performance of 1b or less in the ASTM D-130 test at 100 ° C. for 24 hours. This may produce a result of 1a under the test conditions described above. This may produce results of 1b or less, such as 1a, when the ASTM D-130 test is conducted at 120 ° C or higher for 24 hours. Preferably this produces such a result, as described above, in the absence of copper corrosion additives, or at least in the presence of only such low levels.

In lieu of, or in addition to (preferably in addition to), the use of Fischer-Tropsch derived base oil for one or more of the following purposes: May be used for
i) improving the oxidative stability of the formulation;
ii) improve the cold flow properties of the formulation;
iii) improve the rust resistance of the formulation,
iv) improve the loading performance of the formulation as measured using, for example, standard test method ASTM D-2596 (Four Ball Fusing Load Test),
v) improve the mechanical stability of the formulation;
vi) Improve oil separation tendency of the formulation.

  In particular, Fischer-Tropsch derived base oil may be used for the purpose of improving the rust resistance of the formulation.

  In order for grease formulations to meet current performance specifications and / or meet consumer requirements, the above characteristics typically need to be monitored and adjusted. For example, a specific level of cold flow performance (eg, maximum pour point) may be desirable to meet applicable specifications, a specific minimum kinematic viscosity, a specific level of oxidative stability, and / or a specific level of mechanical stability are desirable. It may be. In accordance with the present invention, inclusion of a Fischer-Tropsch derived base oil may allow all such specifications to be achieved simultaneously in the presence of additives, often with reduced or even none levels.

  The oxidative stability of a grease formulation may be measured using standard or similar methods such as ASTM D-942. “Improvement” of the oxidative stability of grease formulations is similar to the oxidative stability of formulations prior to incorporation of Fischer-Tropsch derived base oil or otherwise containing non-Fischer-Tropsch derived base oil Includes any degree of improvement compared to the formulation. This may involve, for example, adjusting the oxidative stability of the formulation with a Fischer-Tropsch derived base oil to achieve or exceed a desired goal.

  The cold flow characteristics of a grease formulation may reflect its ease of handling at low temperatures, for example below 0 ° C. This may be assessed using tests such as low temperature torque (ASTM D-4693) or flow pressure (DIN 51805) tests. “Improved” cold flow properties of grease formulations are similar in comparison to the cold flow properties of formulations prior to incorporation of Fischer-Tropsch derived base oils or otherwise containing non-Fischer-Tropsch derived base oils Includes any degree of improvement compared to the formulation. This may involve, for example, adjusting the cold flow characteristics of the formulation with a Fischer-Tropsch derived base oil to achieve or exceed a desired goal.

  The rust resistance of a grease formulation may be measured using standard methods such as IP 220 or similar methods. “Improved” rust resistance of grease formulations is similar to rust resistance of formulations prior to incorporation of Fischer-Tropsch derived base oil or otherwise similar to containing non-Fischer-Tropsch derived base oil Includes any degree of improvement compared to the formulation. This may involve, for example, adjusting the rust resistance of the formulation with a Fischer-Tropsch derived base oil to achieve or exceed a desired goal.

  The mechanical stability of a grease formulation may be measured using standard or similar methods such as ASTM D-1831. An “improvement” in the mechanical stability of a grease formulation is compared to the mechanical stability of the formulation prior to incorporating a Fischer-Tropsch derived base oil or otherwise containing a non-Fischer-Tropsch derived base oil. Includes any degree of improvement compared to similar formulations. This may involve, for example, adjusting the mechanical stability of the formulation with a Fischer-Tropsch derived base oil to achieve or exceed a desired goal.

  The separation tendency of a grease formulation may be measured using standard methods such as IP 121 or similar methods. “Improvement” of oil separation tendency of grease formulations is similar in comparison to oil separation tendency of formulations prior to incorporation of Fischer-Tropsch derived base oils or otherwise containing non-Fischer-Tropsch derived base oils Includes any degree of improvement compared to the formulation. This may involve adjusting the oil separation tendency of the formulation, for example, with a Fischer-Tropsch derived base oil to achieve or exceed a desired goal.

  In the context of the present invention, the “use” of a Fischer-Tropsch derived base oil in a grease formulation typically includes one or more thickeners and optionally one or more such as those described above. It is meant that the base oil is incorporated into the formulation as a blend with the additive (ie, a physical mixture).

  Such use may also be, for example, a desired target level of wear resistance or copper corrosion performance, and / or a desired target level of rust resistance, and / or a desired target level of oxidative stability, and / or desired Achieving the objectives of the second and / or third aspects of the present invention, such as to achieve a target viscosity and / or desired target cold flow properties and / or reduce additive concentration in the formulation Providing a Fischer-Tropsch derived base oil with instructions for its use in a grease formulation.

  As noted above, the presence of a Fischer-Tropsch derived base oil in a grease formulation according to the present invention can provide a surprising enhancement in the wear resistance performance of the formulation. This in turn allows the use of lower concentrations of antiwear additives, or in some cases such additives are completely unnecessary. In other words, inclusion of a Fischer-Tropsch derived base oil allows potentially lower levels of antiwear additives to be used in grease formulations to achieve the desired target level of antiwear performance. become.

  Thus, according to a fourth aspect, the present invention provides the use of a Fischer-Tropsch derived base oil in a grease formulation for the purpose of reducing the anti-wear additive concentration in the formulation.

  An anti-wear additive may be defined as an additive that improves the anti-wear characteristics of a lubricant or grease formulation. Examples of known anti-wear additives used in grease formulations include metal dialkyl dithiophosphates, metal dialkyl dithiocarbamates, metal free dialkyl dithioliphosphates, metal free dialkyl dithiocarbamates, full or partial esters of phosphoric acid , And complete or partial esters of boric acid.

  In the context of this fourth aspect of the invention, the term “reduction” encompasses any degree of reduction, for example 10% or more, preferably 15 or 20 or 25% or more of the original antiwear additive concentration. . The reduction may be, for example, 10-75%, or 25-50% of the original antiwear additive concentration. In some cases, the reduction may be 100%, i.e. a reduction to zero anti-wear additive concentration. The reduction is in the context of its intended application compared to the additive concentration that would otherwise be incorporated into the grease formulation to achieve the required properties and performance. May be reduced. This may be present, for example, in a formulation prior to the recognition that a Fischer-Tropsch derived base oil can be used in the manner provided by the present invention, or used in a similar context before adding a Fischer-Tropsch derived base oil. Otherwise intended to be present in similar formulations (eg commercially available) or otherwise similar formulations containing non-Fischer-Tropsch derived (especially mineral derived) base oils It may be the additive concentration present therein.

  The (active substance) concentration of the antiwear additive in the grease formulation prepared according to the invention may be 10,000 ppmw or less, preferably 8000 or 5000 ppmw or less, for example 5000 to 1000 ppmw. The formulation may contain no or substantially no antiwear additives.

  As mentioned above, inclusion of a Fischer-Tropsch derived base oil can provide additional benefits to grease formulations, with correspondingly higher thickener concentrations. This in turn allows other grease additives to be used at even lower levels than more conventional mineral-based formulations.

  According to a fifth aspect, for example, the present invention provides the use of a Fischer-Tropsch derived base oil in a grease formulation for the purpose of reducing the copper corrosion additive concentration in the formulation.

  A copper corrosion additive may be defined as an additive that improves the copper corrosion performance of a lubricant or grease formulation. Examples of known copper corrosion additives used in grease formulations include benzotriazole, tolutriazole, and zinc oxide.

  The concentration of the copper corrosion additive (active substance) in the grease formulation prepared according to the present invention may be 500 ppmw or less, preferably 250 ppmw or less, such as 250-100 ppmw. The formulation may contain no or substantially no copper corrosion additive.

  A sixth aspect of the present invention provides the use of a Fischer-Tropsch derived base oil in a grease formulation for the purpose of reducing the antioxidant additive concentration in the formulation.

  Antioxidant additives reduce the tendency of a grease formulation, or any of its components, to oxidize, including those through an auto-oxidation process, and / or reduce the storage stability of the formulation in the presence of oxygen. It may be defined as an additive that improves. Examples of known antioxidants used in grease formulations include organic amine compounds such as diphenylamine and substituted diphenylamines, phenyl-α-naphthylamine and substituted phenyl α-naphthylamine, and quinoline compounds such as polymerized trimethyldihydroquinoline. And organic phenol compounds and organic sulfur compounds.

  The (active substance) concentration of the antioxidant additive in the grease formulation prepared according to the present invention may be 5000 ppmw or less, preferably 2500 ppmw or less, for example 2500-500 ppmw. The formulation may contain no or substantially no antioxidant additive.

  A seventh aspect of the present invention provides the use of a Fischer-Tropsch derived base oil in a grease formulation for the purpose of reducing the viscosity modifying additive concentration in the formulation.

  Viscosity adjusting additives may be defined as additives that reduce the rate of change of fluid viscosity with temperature. Examples of known viscosity modifying additives used in grease formulations include hydrocarbon polymers such as ethylene-propylene polymers, ethylene-propylene-diene-monomer polymers, and acrylic acid polymers.

  The (active substance) concentration of the viscosity adjusting additive in a grease formulation prepared according to the present invention may be 1000 ppmw or less, preferably 500 or 250 ppmw or less, for example 250-50 ppmw. The formulation preferably contains no or substantially no viscosity modifier additive.

  The eighth aspect of the present invention provides the use of a Fischer-Tropsch derived base oil in a grease formulation for the purpose of reducing the cold flow or flow modifying additive concentration in the formulation.

  A cold flow additive may be defined as any material that can improve the cold flow properties of the formulation as described above. A flow improving additive is a material that can improve the flowability or tendency of the formulation at any given temperature.

  Examples of known cold flow additives include, for example, polyalkylmethacrylates of various molecular weights and structures.

  The (active substance) concentration of the cold flow additive in grease formulations prepared according to the present invention may be up to 250 ppmw, preferably up to 100 ppmw. Its (active substance) concentration is suitably at least 10 ppmw, preferably at least 50 ppmw. The formulation may contain little or substantially no cold flow additive.

  A ninth aspect provides the use of a Fischer-Tropsch derived base oil in a grease formulation for the purpose of reducing the concentration of rust inhibitor additives in the formulation.

  Anti-rust additive is defined as an additive provided by a lubricant or grease formulation that improves resistance to rust on a steel or iron surface that is in contact with water but protected by a film of the lubricant or grease formulation. May be. Examples of known anti-rust additives used in grease formulations include neutral metal organic sulfonates, overbased metal organic sulfonates, metal naphthenates, monobasic, dibasic and Examples thereof include metal salts of polybasic carboxylic acids and alkyl succinic acid reaction products.

  The (active substance) concentration of the anticorrosive additive in the grease formulation prepared according to the present invention may be 5000 ppmw or less, preferably 2000 ppmw or less, for example 2000-500 ppmw. The formulation may contain no or substantially no rust inhibitor.

  In the context of the fifth to ninth aspects of the invention, the term “reduced” has the same meaning as in the context of the fourth aspect, mutatis mutandis.

  A tenth aspect of the invention thereby increases the viscosity of the thickener in order to achieve one or more of the advantages described above in connection with the second to ninth aspects of the invention. The use of a Fischer-Tropsch derived base oil in a grease formulation containing a viscous agent is provided.

  According to an eleventh aspect, the present invention provides a method of preparing a grease formulation, such as a grease formulation according to the first aspect, optionally comprising one or more additives, a thickener and Mixing the Fischer-Tropsch derived base oil together. The method may be implemented for one or more of the purposes described above in connection with the second through tenth aspects. Other preferred features of this aspect of the invention may be as described above in connection with the first to tenth aspects, in particular the thickener may comprise soap.

  The method of the eleventh aspect may involve preparing a thickener, for example a soap-based thickener, in a Fischer-Tropsch derived base oil and subsequently incorporating any desired additives into the resulting mixture. Good.

  A twelfth aspect is a grease formulation according to the first aspect of the present invention and / or a grease formulation prepared according to any one of the second to eleventh aspects as a lubricant in an apparatus. A method for operating a mechanical equipment article is provided. The grease formulation may be used in the device to benefit from one or more of the advantages described above. Equipment articles include, for example, automotive wheel hubs; industrial machinery; electric motors; transmission joints such as constant velocity joints; automotive steering joints or cardan shafts; or rolling element bearings in gear assemblies such as conveyor drive gears. May be.

  According to a thirteenth aspect, the present invention provides a mechanical equipment article containing a grease formulation according to the first aspect and / or a grease formulation prepared according to any one of the second to eleventh aspects. provide.

  Throughout the description and claims, the terms “comprise” and “contain” and variations of those terms, eg, “comprising” and “comprises” It means "including but not limited to" and is not intended (and not excluded) to exclude other parts, additives, components, integers or steps.

  Throughout this description and the claims, the singular includes the plural unless the context demands that the context be plural. Specifically, when indefinite articles are used, it is understood that the specification contemplates the plural as well as the singular unless the context requires it to be plural.

  Preferred features of each aspect of the invention may be as described in connection with any of the other aspects.

  Other features of the present invention will become apparent from the following examples. Generally speaking, the present invention extends to any one of the novel features disclosed herein (including any appended claims and drawings), or any novel combination thereof. Features, integers, properties, compounds, chemical moieties or chemical groups described in connection with a particular aspect, embodiment or example of the invention, unless otherwise inconsistent, any other aspect described herein, It is understood that the present invention can be applied to the embodiment or the example.

  Further, unless otherwise specified, any feature disclosed herein may be replaced by an alternative feature serving the same or similar purpose.

  The following examples illustrate the properties and performance of grease formulations according to the present invention.

  Lithium grease formulations according to the present invention were prepared and tested for their properties and compared to standard commercially available mineral oil based greases.

  Each formulation contained a large proportion of Fischer-Tropsch derived base oil. The two base oils used, BO-1 and BO-2, had the properties shown in Table 1 below. They were prepared using a Fischer-Tropsch method similar to that described above.

  Fischer-Tropsch derived base oil has a high viscosity index, low pour point (eg about 10 or 20 ° C. lower than typical mineral-derived “Group I” base oils for heavy base oil BO-1), high flammability It can be seen that it has a point, and a low evaporation rate, which is potentially beneficial for stability under higher temperature operating conditions. The heaviest oil BO-1 is slightly turbid in appearance due to the presence of a small number of residual wax crystals that are not removed during its manufacture, but this is not a problem in grease formulations, and the properties of the final product It is not considered to affect. However, due to this turbidity, the viscosity of BO-1 could not be measured accurately at 40 ° C. Therefore, the values shown in Table 1 are calculated from the values measured at 100 and 70 ° C.

Example 1
A lithium grease formulation GF-1 containing base oil BO-1 was prepared using a standard Pretzsch kettle procedure.

  1100 g base oil, 330 g hydrogenated castor oil, and 46.2 g lithium hydroxide were placed in a Pretzsch kettle with 50 g water. The mixture was heated to approximately 150 ° C. with stirring in a sealed kettle. The steam was evacuated and heating was continued to approximately 220 ° C. The reaction mass was then cooled.

  From 200 to 165 ° C, cooling was performed at a rate of 1 ° C per minute. At a charge temperature of 163 ° C., 723.8 g of base oil was added over 10 minutes. The oil cooler was then switched on. When the grease cooled to room temperature, it was homogenized by passing it once, for example, through a three-roll kneader.

  The finished formulation GF-1 was a light beige grease containing 82.9 wt% base oil, 15 wt% hydrogenated castor oil, and 2.1 wt% lithium hydroxide. The total soap content was close to what was predicted to be necessary to produce a grease with a permeation number around 280, based on oil polarity and viscosity data.

  GF-1 did not contain any performance enhancing additives.

  Several relevant properties of the grease formulation GF-1 were measured using standard test methods as well as several additional test procedures. The same properties were also measured for a commercially available mineral oil based grease formulation GF-A (ex-Shell). The results are shown in Table 2 below.

  The yield of GF-1 (ie, the amount of thickener required to achieve a specific consistency or penetration value) is significantly lower than that of conventional mineral oil greases and lower than that of Fischer-Tropsch base oil. The prediction based on polarity was confirmed. Fischer-Tropsch derived oils are known to require up to 75% more thickener than typical mineral-derived “Group I” base oils.

  Higher thickener content is also known to provide improved mechanical stability and lower oil separation. This was confirmed by the data in Table 2, which shows that the stability and oil separation of GF-1 far surpasses conventional mineral oil based greases. In fact, the oil separation of GF-1 at 80 ° C. is almost equal to the conventional lithium grease at 40 ° C. These stability and oil separation benefits were reflected in the results of the wheel bearing leak test at 130 ° C., and the performance of GF-1 usually appeared to be that expected for a good complex grease. These results were better than expected because a Fischer-Tropsch derived base oil was used instead of the mineral base oil based on GF-A.

  More surprising is the result of the four-ball wear test. The performance of the grease formulation of the present invention was outstanding, especially considering that it did not contain any recognized anti-wear additive. GF-1 gave an even higher antiwear effect than provided by a base grease containing a lower thickener amount.

  GF-1 also gave excellent results in the Emcor rust test with distilled water. This is also surprising for additive-free grease.

  The copper corrosion test results of GF-1 reaching up to 150 ° C. were also outstanding.

  The results of the oxidation test are also well within the normal specification range of the standard grease formulation, despite the absence of antioxidants.

  Overall, the properties and performance of the grease formulations according to the present invention are well within the specifications of a typical high quality grease and in many respects. For example, its stability matches better with a lithium complex grease rather than a typical lithium hydroxide grease. Its performance in the four-ball wear resistance test is comparable to high quality antiwear additive-containing grease, despite the fact that GF-1 itself contains no additive.

Example 2
A second lithium grease formulation GF-2 according to the present invention was prepared using base oil BO-2. The preparation method was as described in Example 1.

  The finished formulation GF-2 is a light beige, almost white grease containing 84.9% by weight base oil, 13.2% by weight hydrogenated castor oil, and 1.9% by weight lithium hydroxide. there were.

  Several relevant properties of the grease formulation GF-2 were measured using standard test methods. The same properties were also measured for a commercially available mineral oil based grease formulation GF-B (ex-Shell). The results are shown in Table 3 below.

  Neither GF-2 nor GF-B contained any performance enhancing additives.

  From the data in Table 3, Fischer-Tropsch base oil BO-2 has significantly more thickener (in this case 47% more than conventional mineral oil) to make a grease of a specific consistency. ) Is confirmed. This demonstrates that the effect is generally applicable to Fischer-Tropsch derived oils as well as certain high viscosity grades represented by BO-1.

  In addition, Table 3 confirms that the increased thickener content resulting from the use of Fischer-Tropsch derived base oils provides even better wear resistance performance than the corresponding greases made with conventional mineral base oils. Is done.

  Accordingly, it will be appreciated that the present invention provides grease formulations with improved performance and / or allows the preparation of greases with additive levels lower than previously required to meet performance specifications. Can do. Lower additive levels can reduce the cost and time required for subsequent manufacturing, as well as additive levels such as meeting legal requirements and meeting consumer expectations and / or protecting users And the effort required to monitor quality can be reduced.

Example 3
A lithium complex grease formulation GF-3 was prepared in accordance with the present invention, its properties were tested and compared to a standard commercially available mineral oil based grease GF-C. Formulation GF-3 contained a high proportion of Fischer-Tropsch derived base oil BO-1 listed in Table 1 above. It was prepared using the following method based on the standard Pretzsch kettle procedure.

In a ratio of 1 part solid to 5 parts water, LiOH. A slurry of H ₂ O, boric acid, salicylic acid, and water was added to the hydrogenated castor oil fatty acid in the cold base oil. The mixture was heated to 170 ° C. in a sealed autoclave. After evacuating the steam and continuing heating to 220 ° C., the reaction mass was cooled to homogenize the product. The finished formulation GF-3 contained 76.2 wt% base oil and 12.6 wt% hydrogenated castor oil. It did not contain any performance enhancing additives and the appearance was light beige.

  Some relevant properties of the grease formulation GF-3 were measured using standard test methods. The same properties were also measured for a commercially available mineral oil based lithium complex EP (extreme pressure) grease formulation GF-C (ex-Shell). The results are shown in Table 4 below.

  Again, the yield of GF-3 was significantly lower than conventional mineral oil greases, confirming predictions based on the lower polarity of Fischer-Tropsch base oil.

  The data in Table 4 shows that the stability and oil separation of GF-3 is consistent with the conventional mineral-based grease formulation GF-C.

  The dropping point of GF-3 is higher than that of GF-C, because GF-3 contains no additive. Many additives are known to reduce or suppress the dropping point of the grease, and the absence of any additive removes the risk of this occurring.

  More surprising is the result of the four-ball fusion test. The performance of the additive-free grease formulation of the present invention (GF-3) is based on the GF containing EP additive for the clear purpose of improving extreme pressure grease properties, including performance in a four-ball fusion test. Same as -C. The performance of GF-3 in the Fafnir fretting test, another indicator of EP / wear properties, was also better than additive containing mineral oil based grease GF-C.

  Equally surprisingly, the results of the GF-3 oxidation test were consistent with the mineral oil benchmark GF-C after 100 hours of testing, but significantly better than GF-C after 400 hours. there were. This suggests the oxidation resistance inherent in GF-3 even without the oxidation-inhibiting additive as contained in GF-C.

  The FAG FE-9 bearing life test at 150 ° C. provides further excellent evidence for the effectiveness of the high thickener content grease forming properties of Fischer-Tropsch base oil. The grease GF-3 of the present invention exceeds the 100-hour operating time required for a fully added high performance lithium complex grease, despite the absence of any chemical additives of the type described above.

GB-B-2077289 specification EP-A-0147873 specification EP-A-0583836 specification U.S. Pat. No. 4,125,566 U.S. Pat. No. 4,478,955 EP-A-0583836 specification International Publication No. 02070629 Pamphlet US Pat. No. 7,053,254

"The Shell Middle Distillate Synthesis Process" published by van der Burgt et al., Published at the 5th Synfuels World Symposium, Washington DC in November 1985.

Claims (8)

A grease formulation comprising a thickener and a Fischer-Tropsch derived base oil, the Fischer-Tropsch derived base oil having a kinematic viscosity at 100 ° C. of 8-30 mm ² / s, wherein the thickener is a soap And the grease formulation comprises 10% by weight or more of the thickener. The grease formulation of claim 1, wherein the Fischer-Tropsch derived base oil has a kinematic viscosity at 100 ° C. of 8-25 mm ² / s. The grease formulation of claim 1, wherein the Fischer-Tropsch derived base oil has a kinematic viscosity at 100 ° C. of 10-25 mm ² / s. Use of a Fischer-Tropsch derived base oil in a formulation comprising a thickener for the purpose of improving the anti-wear performance of a grease formulation , wherein the Fischer-Tropsch derived base oil is 8-30 mm ² at 100 ° C. The use wherein the thickener comprises soap and the grease formulation comprises 10% or more by weight of the thickener . Use of a Fischer-Tropsch derived base oil in a formulation comprising a thickener for the purpose of improving the copper corrosion performance of a grease formulation , wherein the Fischer-Tropsch derived base oil is 8-30 mm ² at 100 ° C. The use wherein the thickener comprises soap and the grease formulation comprises 10% or more by weight of the thickener . Fischer-Tropsch derived base oil
i ) improving the cold flow properties of the formulation;
ii ) improve the rust resistance of the formulation;
iii ) improving the loading performance of the formulation as measured using the standard four ball fusion load test method ASTM D-2596;
iv ) Use according to claim 4 or 5 used for one or more purposes of improving the oil separation tendency of the formulation. Use of a Fischer-Tropsch derived base oil in a grease formulation containing a thickener for the purpose of reducing the additive concentration in the formulation , wherein the Fischer-Tropsch derived base oil is 8 to Said use having a kinematic viscosity of 30 mm ² / s, wherein said thickener comprises soap and said grease formulation comprises 10% by weight or more of said thickener .   8. Use according to claim 7, wherein the additive is an anti-wear additive or a copper corrosion additive.